# contourf

filled level curves of a surface on a 2D plot

### Syntax

contourf(x, y, z, nz, [style, strf, leg, rect, nax, fpf])

### Arguments

- x, y
two real row vectors of size

`n1`

and`n2`

: the grid.- z
a real matrix of size

`(n1,n2)`

, the values of the function.- nz
the level values or the number of levels.

- -
If

`nz`

is an integer, its value gives the number of level curves equally spaced from`zmin`

to`zmax`

as follows:z= zmin + (1:nz)*(zmax-zmin)/(nz+1)

Note: that the`zmin`

and`zmax`

levels are not drawn (generically they are reduced to points) but they can be added with- -
If

`nz`

is a vector,`nz(i)`

gives the value of the`i`

-th level curve.

- style, strf, leg, rect, nax
see

`plot2d`

. The argument`style`

gives the colors which are to be used for level curves. It must have the same size as the number of levels.- fpf
You can change the format of the floating point number printed on the levels where

`fpf`

is the format in C format syntax (for example`fpf="%.3f"`

). Set`fpf`

to " " implies that the level are not drawn on the level curves. If not given, the default format of contour2d is used.

### Description

`contourf`

paints surface between two consecutive
level curves of a surface `z=f(x,y)`

on a 2D plot.
The values of `f(x,y)`

are given by the matrix
`z`

at the grid points defined by
`x`

and `y`

.

Enter the command `contourf()`

to see a demo.

### Examples

contourf(1:10,1:10,rand(10,10),5,1:5,"011"," ",[0,0,11,11])

function z=peaks(x, y) x1=x(:).*.ones(1,size(y,'*')); y1=y(:)'.*.ones(size(x,'*'),1); z = (3*(1-x1).^2).*exp(-(x1.^2) - (y1+1).^2) ... - 10*(x1/5 - x1.^3 - y1.^5).*exp(-x1.^2-y1.^2) ... - 1/3*exp(-(x1+1).^2 - y1.^2) endfunction function z=peakit() x=-4:0.1:4;y=x;z=peaks(x,y); endfunction z=peakit(); levels=[-6:-1,-logspace(-5,0,10),logspace(-5,0,10),1:8]; m=size(levels,'*'); n = fix(3/8*m); r = [(1:n)'/n; ones(m-n,1)]; g = [zeros(n,1); (1:n)'/n; ones(m-2*n,1)]; b = [zeros(2*n,1); (1:m-2*n)'/(m-2*n)]; h = [r g b]; gcf().color_map = h; clf(); contourf([],[],z,[-6:-1,-logspace(-5,0,10),logspace(-5,0,10),1:8]);

### See also

- contour — level curves on a 3D surface
- contour2d — level curves of a surface on a 2D plot
- contour2di — compute level curves of a surface on a 2D plot
- plot2d — 2D plot

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